[cdi-dev] Proxy implementation leaks

[Pete Muir]

On 9 May 2011, at 15:49, Pete Muir wrote:

> 
> On 9 May 2011, at 15:46, Christian Bauer wrote:
> 
>> Started working with Weld 1.1.1 and found two issues that probably should be addressed (maybe just documented). They both look to me like leaking implementation details because proxies are used for components which are not @Singleton or @Dependent.
>> 
>> @ApplicationScoped
>> public class Bug {
>> 
>>  public Bug() {
>>      System.out.println("########## CONSTRUCT");
>>  }
>> 
>>  public void foo() {
>>      System.out.println("##### FOO");
>>  }
>> 
>>  public static void main(String[] args) {
>>      Weld weld = new Weld();
>>      WeldContainer weldContainer = weld.initialize();
>> 
>>      Bug bug = weldContainer.instance().select(Bug.class).get(); // Creates new instance of Bug
>>      bug.foo(); // Creates new instance of Bug!!!
>>      bug.foo(); // Uses existing instance
>> 
>>      weld.shutdown();
>>  }
>> }
>> 
>> The proxy of Bug will call its superclass constructor several times during the lifecycle of the Bug component. I don't know if that is really necessary, but if it is, you can now no longer use constructors to initialize your component. This is an issue because
>> 
>> - it's not documented that constructors of @ApplciationScoped (etc., proxied) components behave differently than @Singleton/@Dependent constructors
>> 
>> - even if it's documented, it's questionable if that really should be the case.
>> 
>> Taking away constructors as the primary means of initializing a component - e.g. obtaining resources such as database connections, reading config files, etc. - is a major change in the Java programming model. Users have to be strongly advised to use @PostConstruct then.
> 
> Stuart, I though subclassing proxies should resolve this?

We can also consider requiring impl's to only call ctors once only.https://issues.jboss.org/browse/CDI-126